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Tang L, Bednar RM, Rozanov ND, Hemshorn ML, Mehl RA, Fang C. Rational Design for High Bioorthogonal Fluorogenicity of Tetrazine-Encoded Green Fluorescent Proteins. Nat Sci (Weinh) 2022; 2:e20220028. [PMID: 36440454 PMCID: PMC9699285 DOI: 10.1002/ntls.20220028] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The development of bioorthogonal fluorogenic probes constitutes a vital force to advance life sciences. Tetrazine-encoded green fluorescent proteins (GFPs) show high bioorthogonal reaction rate and genetic encodability, but suffer from low fluorogenicity. Here, we unveil the real-time fluorescence mechanisms by investigating two site-specific tetrazine-modified superfolder GFPs via ultrafast spectroscopy and theoretical calculations. Förster resonance energy transfer (FRET) is quantitatively modeled and revealed to govern the fluorescence quenching; for GFP150-Tet with a fluorescence turn-on ratio of ~9, it contains trimodal subpopulations with good (P1), random (P2), and poor (P3) alignments between the transition dipole moments of protein chromophore (donor) and tetrazine tag (Tet-v2.0, acceptor). By rationally designing a more free/tight environment, we created new mutants Y200A/S202Y to introduce more P2/P1 populations and improve the turn-on ratios to ~14/31, making the fluorogenicity of GFP150-Tet-S202Y the highest among all up-to-date tetrazine-encoded GFPs. In live eukaryotic cells, the GFP150-Tet-v3.0-S202Y mutant demonstrates notably increased fluorogenicity, substantiating our generalizable design strategy.
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Affiliation(s)
- Longteng Tang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, USA
| | - Riley M. Bednar
- Department of Biochemistry and Biophysics, Oregon State University, 2011 Agricultural and Life Sciences Building, Corvallis, Oregon 97331-7305, USA
| | - Nikita D. Rozanov
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, USA
| | - Marcus L. Hemshorn
- Department of Biochemistry and Biophysics, Oregon State University, 2011 Agricultural and Life Sciences Building, Corvallis, Oregon 97331-7305, USA
| | - Ryan A. Mehl
- Department of Biochemistry and Biophysics, Oregon State University, 2011 Agricultural and Life Sciences Building, Corvallis, Oregon 97331-7305, USA
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, USA
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Tang L, Zhang S, Zhao Y, Rozanov ND, Zhu L, Wu J, Campbell RE, Fang C. Switching between Ultrafast Pathways Enables a Green-Red Emission Ratiometric Fluorescent-Protein-Based Ca 2+ Biosensor. Int J Mol Sci 2021; 22:E445. [PMID: 33466257 PMCID: PMC7794744 DOI: 10.3390/ijms22010445] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 12/30/2020] [Accepted: 12/31/2020] [Indexed: 01/25/2023] Open
Abstract
Ratiometric indicators with long emission wavelengths are highly preferred in modern bioimaging and life sciences. Herein, we elucidated the working mechanism of a standalone red fluorescent protein (FP)-based Ca2+ biosensor, REX-GECO1, using a series of spectroscopic and computational methods. Upon 480 nm photoexcitation, the Ca2+-free biosensor chromophore becomes trapped in an excited dark state. Binding with Ca2+ switches the route to ultrafast excited-state proton transfer through a short hydrogen bond to an adjacent Glu80 residue, which is key for the biosensor's functionality. Inspired by the 2D-fluorescence map, REX-GECO1 for Ca2+ imaging in the ionomycin-treated human HeLa cells was achieved for the first time with a red/green emission ratio change (ΔR/R0) of ~300%, outperforming many FRET- and single FP-based indicators. These spectroscopy-driven discoveries enable targeted design for the next-generation biosensors with larger dynamic range and longer emission wavelengths.
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Affiliation(s)
- Longteng Tang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331-4003, USA; (L.T.); (N.D.R.); (L.Z.)
| | - Shuce Zhang
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada; (S.Z.); (Y.Z.); (J.W.); or
| | - Yufeng Zhao
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada; (S.Z.); (Y.Z.); (J.W.); or
| | - Nikita D. Rozanov
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331-4003, USA; (L.T.); (N.D.R.); (L.Z.)
| | - Liangdong Zhu
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331-4003, USA; (L.T.); (N.D.R.); (L.Z.)
| | - Jiahui Wu
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada; (S.Z.); (Y.Z.); (J.W.); or
| | - Robert E. Campbell
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada; (S.Z.); (Y.Z.); (J.W.); or
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331-4003, USA; (L.T.); (N.D.R.); (L.Z.)
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Oscar BG, Zhu L, Wolfendeen H, Rozanov ND, Chang A, Stout KT, Sandwisch JW, Porter JJ, Mehl RA, Fang C. Dissecting Optical Response and Molecular Structure of Fluorescent Proteins With Non-canonical Chromophores. Front Mol Biosci 2020; 7:131. [PMID: 32733917 PMCID: PMC7358599 DOI: 10.3389/fmolb.2020.00131] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 06/02/2020] [Indexed: 12/21/2022] Open
Abstract
Tracking the structural dynamics of fluorescent protein chromophores holds the key to unlocking the fluorescence mechanisms in real time and enabling rational design principles of these powerful and versatile bioimaging probes. By combining recent chemical biology and ultrafast spectroscopy advances, we prepared the superfolder green fluorescent protein (sfGFP) and its non-canonical amino acid (ncAA) derivatives with a single chlorine, bromine, and nitro substituent at the ortho site to the phenolate oxygen of the embedded chromophore, and characterized them using an integrated toolset of femtosecond transient absorption and tunable femtosecond stimulated Raman spectroscopy (FSRS), aided by quantum calculations of the vibrational normal modes. A dominant vibrational cooling time constant of ~4 and 11 ps is revealed in Cl-GFP and Br-GFP, respectively, facilitating a ~30 and 12% increase of the fluorescent quantum yield vs. the parent sfGFP. Similar time constants were also retrieved from the transient absorption spectra, substantiating the correlated electronic and vibrational motions on the intrinsic molecular timescales. Key carbon-halogen stretching motions coupled with phenolate ring motions of the deprotonated chromophores at ca. 908 and 890 cm-1 in Cl-GFP and Br-GFP exhibit enhanced activities in the electronic excited state and blue-shift during a distinct vibrational cooling process on the ps timescale. The retrieved structural dynamics change due to targeted site-specific halogenation of the chromophore thus provides an effective means to design new GFP derivatives and enrich the bioimaging probe toolset for life and medical sciences.
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Affiliation(s)
- Breland G. Oscar
- Department of Chemistry, Oregon State University, Corvallis, OR, United States
| | - Liangdong Zhu
- Department of Chemistry, Oregon State University, Corvallis, OR, United States
| | - Hayati Wolfendeen
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, United States
| | - Nikita D. Rozanov
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR, United States
| | - Alvin Chang
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR, United States
| | - Kenneth T. Stout
- Department of Chemistry, Oregon State University, Corvallis, OR, United States
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR, United States
| | - Jason W. Sandwisch
- Department of Chemistry, Oregon State University, Corvallis, OR, United States
| | - Joseph J. Porter
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, United States
| | - Ryan A. Mehl
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, United States
| | - Chong Fang
- Department of Chemistry, Oregon State University, Corvallis, OR, United States
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Tollefson EJ, Allen CR, Chong G, Zhang X, Rozanov ND, Bautista A, Cerda JJ, Pedersen JA, Murphy CJ, Carlson EE, Hernandez R. Preferential Binding of Cytochrome c to Anionic Ligand-Coated Gold Nanoparticles: A Complementary Computational and Experimental Approach. ACS Nano 2019; 13:6856-6866. [PMID: 31082259 DOI: 10.1021/acsnano.9b01622] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Membrane-bound proteins can play a role in the binding of anionic gold nanoparticles (AuNPs) to model bilayers; however, the mechanism for this binding remains unresolved. In this work, we determine the relative orientation of the peripheral membrane protein cytochrome c in binding to a mercaptopropionic acid-functionalized AuNP (MPA-AuNP). As this is nonrigid binding, traditional methods involving crystallographic or rigid molecular docking techniques are ineffective at resolving the question. Instead, we have implemented a computational assay technique using a cross-correlation of a small ensemble of 200 ns long molecular dynamics trajectories to identify a preferred nonrigid binding orientation or pose of cytochrome c on MPA-AuNPs. We have also employed a mass spectrometry-based footprinting method that enables the characterization of the stable protein corona that forms at long time-scales in solution but remains in a dynamic state. Through the combination of these computational and experimental primary results, we have established a consensus result establishing the identity of the exposed regions of cytochrome c in proximity to MPA-AuNPs and its complementary pose(s) with amino-acid specificity. Moreover, the tandem use of the two methods can be applied broadly to determine the accessibility of membrane-binding sites for peripheral membrane proteins upon adsorption to AuNPs or to determine the exposed amino-acid residues of the hard corona that drive the acquisition of dynamic soft coronas. We anticipate that the combined use of simulation and experimental methods to characterize biomolecule-nanoparticle interactions, as demonstrated here, will become increasingly necessary as the complexity of such target systems grows.
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Affiliation(s)
- Emily J Tollefson
- Department of Chemistry , University of Minnesota-Twin Cities , Minneapolis , Minnesota 55455 , United States
| | - Caley R Allen
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Gene Chong
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Xi Zhang
- Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Nikita D Rozanov
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Anthony Bautista
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Jennifer J Cerda
- Department of Chemistry , University of Minnesota-Twin Cities , Minneapolis , Minnesota 55455 , United States
| | - Joel A Pedersen
- Environmental Chemistry and Technology Program , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Catherine J Murphy
- Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Erin E Carlson
- Department of Chemistry , University of Minnesota-Twin Cities , Minneapolis , Minnesota 55455 , United States
| | - Rigoberto Hernandez
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , United States
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Taylor MA, Zhu L, Rozanov ND, Stout KT, Chen C, Fang C. Delayed vibrational modulation of the solvated GFP chromophore into a conical intersection. Phys Chem Chem Phys 2019; 21:9728-9739. [PMID: 31032505 DOI: 10.1039/c9cp01077g] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Green fluorescent protein (GFP) has revolutionized bioimaging and life sciences. Its successes have inspired modification of the chromophore structure and environment to tune emission properties, but outside the protein cage, the chromophore is essentially non-fluorescent. In this study, we employ the tunable femtosecond stimulated Raman spectroscopy (FSRS) and transient absorption (TA) to map the energy dissipation pathways of GFP model chromophore (HBDI) in basic aqueous solution. Strategic tuning of the Raman pump to 550 nm exploits the stimulated emission band to enhance excited state vibrational motions as HBDI navigates the non-equilibrium potential energy landscape to pass through a conical intersection. The time-resolved FSRS uncovers prominent anharmonic couplings between a global out-of-plane bending mode of ∼227 cm-1 and two modes at ∼866 and 1572 cm-1 before HBDI reaches the twisted intramolecular charge transfer (TICT) state on the ∼3 ps time scale. Remarkably, the wavelet transform analysis reveals a ∼500 fs delayed onset of the coupling peaks, in correlation with the emergence of an intermediate charge-separated state en route to the TICT state. This mechanism is corroborated by the altered coupling matrix for the HBDI Raman modes in the 50% (v/v) water-glycerol mixture, and a notable lengthening of the picosecond time constant. The real-time molecular "movie" of the general rotor-like HBDI isomerization reaction following photoexcitation represents a significant advance in comprehending the photochemical reaction pathways of the solvated GFP chromophore, therefore providing a crucial foundation to enable rational design of diverse nanomachines from efficient molecular rotors to bright fluorescent probes.
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Affiliation(s)
- Miles A Taylor
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, USA.
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Rozanov DV, Rozanov ND, Chiotti KE, Reddy A, Wilmarth PA, David LL, Cha SW, Woo S, Pevzner P, Bafna V, Burrows GG, Rantala JK, Levin T, Anur P, Johnson-Camacho K, Tabatabaei S, Munson DJ, Bruno TC, Slansky JE, Kappler JW, Hirano N, Boegel S, Fox BA, Egelston C, Simons DL, Jimenez G, Lee PP, Gray JW, Spellman PT. MHC class I loaded ligands from breast cancer cell lines: A potential HLA-I-typed antigen collection. J Proteomics 2018; 176:13-23. [PMID: 29331515 DOI: 10.1016/j.jprot.2018.01.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 12/01/2017] [Accepted: 01/04/2018] [Indexed: 12/30/2022]
Abstract
To build a catalog of peptides presented by breast cancer cells, we undertook systematic MHC class I immunoprecipitation followed by elution of MHC class I-loaded peptides in breast cancer cells. We determined the sequence of 3196 MHC class I ligands representing 1921 proteins from a panel of 20 breast cancer cell lines. After removing duplicate peptides, i.e., the same peptide eluted from more than one cell line, the total number of unique peptides was 2740. Of the unique peptides eluted, more than 1750 had been previously identified, and of these, sixteen have been shown to be immunogenic. Importantly, half of these immunogenic peptides were shared between different breast cancer cell lines. MHC class I binding probability was used to plot the distribution of the eluted peptides in accordance with the binding score for each breast cancer cell line. We also determined that the tested breast cancer cells presented 89 mutation-containing peptides and peptides derived from aberrantly translated genes, 7 of which were shared between four or two different cell lines. Overall, the high throughput identification of MHC class I-loaded peptides is an effective strategy for systematic characterization of cancer peptides, and could be employed for design of multi-peptide anticancer vaccines. SIGNIFICANCE By employing proteomic analyses of eluted peptides from breast cancer cells, the current study has built an initial HLA-I-typed antigen collection for breast cancer research. It was also determined that immunogenic epitopes can be identified using established cell lines and that shared immunogenic peptides can be found in different cancer types such as breast cancer and leukemia. Importantly, out of 3196 eluted peptides that included duplicate peptides in different cells 89 peptides either contained mutation in their sequence or were derived from aberrant translation suggesting that mutation-containing epitopes are on the order of 2-3% in breast cancer cells. Finally, our results suggest that interfering with MHC class I function is one of the mechanisms of how tumor cells escape immune system attack.
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Affiliation(s)
- Dmitri V Rozanov
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, United States.
| | | | - Kami E Chiotti
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, United States
| | - Ashok Reddy
- Proteomics Shared Resource, Oregon Health and Science University, Portland, OR, United States
| | - Phillip A Wilmarth
- Proteomics Shared Resource, Oregon Health and Science University, Portland, OR, United States
| | - Larry L David
- Proteomics Shared Resource, Oregon Health and Science University, Portland, OR, United States
| | - Seung W Cha
- Electrical and Computer Engineering, University of California, San Diego, CA, United States
| | - Sunghee Woo
- School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Pavel Pevzner
- The NIH Center for Computational Mass Spectrometry, University of California, San Diego, San Diego, CA, United States
| | - Vineet Bafna
- Computer Science & Engineering, University of California, San Diego, CA, United States
| | - Gregory G Burrows
- Neurology and Biochemistry & Molecular Biology, Oregon Health and Science University, Portland, OR, United States
| | | | - Trevor Levin
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR, United States
| | - Pavana Anur
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, United States
| | - Katie Johnson-Camacho
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, United States
| | - Shaadi Tabatabaei
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, United States
| | - Daniel J Munson
- Department of Immunology & Microbiology, University of Colorado, Denver, CO, United States
| | - Tullia C Bruno
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Jill E Slansky
- Department of Immunology & Microbiology, University of Colorado, Denver, CO, United States
| | - John W Kappler
- National Jewish Medical and Research Center, Denver, CO, United States
| | - Naoto Hirano
- Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Sebastian Boegel
- University Medical Center, Johannes Gutenberg-University, Mainz, Germany
| | - Bernard A Fox
- Laboratory of Molecular and Tumor Immunology, Chiles Research Institute Providence PDX Medical Center, Portland, OR, United States
| | - Colt Egelston
- City of Hope National Medical Center, Duarte, CA, United States
| | - Diana L Simons
- City of Hope National Medical Center, Duarte, CA, United States
| | - Grecia Jimenez
- City of Hope National Medical Center, Duarte, CA, United States
| | - Peter P Lee
- City of Hope National Medical Center, Duarte, CA, United States
| | - Joe W Gray
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR, United States; Center for Health & Healing, Oregon Health and Science University, Portland, OR, United States
| | - Paul T Spellman
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, United States
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Oscar BG, Liu W, Rozanov ND, Fang C. Ultrafast intermolecular proton transfer to a proton scavenger in an organic solvent. Phys Chem Chem Phys 2016; 18:26151-26160. [DOI: 10.1039/c6cp05692j] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The structural dynamics basis of intermolecular proton transfer from photoacid to acetate in methanol is revealed using femtosecond stimulated Raman spectroscopy.
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Affiliation(s)
- Breland G. Oscar
- Oregon State University
- Department of Chemistry
- 263 Linus Pauling Science Centre (lab)
- Corvallis
- USA
| | - Weimin Liu
- Oregon State University
- Department of Chemistry
- 263 Linus Pauling Science Centre (lab)
- Corvallis
- USA
| | - Nikita D. Rozanov
- Oregon State University
- Department of Chemistry
- 263 Linus Pauling Science Centre (lab)
- Corvallis
- USA
| | - Chong Fang
- Oregon State University
- Department of Chemistry
- 263 Linus Pauling Science Centre (lab)
- Corvallis
- USA
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